Long-term clinical performance and longevity of gold alloy vs ceramic partial crowns

Cast gold partial crowns (CGPC) are an accepted means of restoring posterior teeth. For aesthetic reasons, gold alloys are being increasingly substituted with ceramics. The aim of the present study was to investigate retrospectively the long-term clinical performance and survival of CGPC and compare the results to the ones already reported for ceramic partial crowns (CPC). The CGPC group consisted of 42 patients (24 male, 18 female) randomly sampled from a total of 106 patients with CGPC, with one restoration per patient. The CPC group consisted of 22 patients with a total of 42 restorations. Both types of restoration were done by one experienced dentist. Another two experienced dentists who were not involved in performing the restorations rated both kinds of partial crowns using the modified United State Public Health Service (USPHS) criteria [14]. The Median age of the CGPC was 57 months (range 3–157) and of the CPC and 63 months (range 24–72). Forty-one (98%) of the CGPC and 27 (64%) of the CPC were placed in molars, the rest in premolars. In each group, 40 (95%) restorations were still functioning without any necessity of replacement. Two teeth with CGPC, in situ for 4.5 and 11 years, respectively, had been extracted for periodontal reasons. Two CPC fractured and had to be replaced after 2 and 6.5 years in situ. The USPHS criteria results were similarly good for the gold and ceramic groups. Kaplan-Meier analysis revealed survival probabilities of 72±21% and 96±4% after 13 and 7 years, respectively, for the CGPC. Survival of the CPC was 81±15% after 7 years. No statistically significant difference among survival functions of CGPC and CPC was found. From this data, it can be concluded that the longevity of CPC is not inferior to that of gold alloys. However, more long-term studies comparing the clinical performance and longevity of these two types of indirect restoration in the posterior region with larger numbers of restorations are desirable.